Phobia (3.5e Flaw)

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Effect: You are afraid of a particular kind of object, creature or environment, as chosen from the list below. You are shaken if you are aware of the presence of something that would trigger your phobia within 30 ft. The condition lasts until the triggering situation is overcome, or 1d6 rounds if the trigger is an instantaneous event.
If the trigger is an object or creature, you become frightened if you touch (or are touched by) the object; or if the creature speaks or makes a cry directly to you.

"We are going to go now? What, in the dark? No way am I going out there? Not without a decent lantern at least!"

Equinophobia

“I don't like horses.” Said Adon, leaning on his bow.
“What's wrong with them? Flondor stroked the neck of a brown stallion. “These are the finest horses south of the Great Mountains.”
Adon shrugged. “Nothing against these horses in particular. But horses are noisy and smelly, and they eat and drink a lot. On this trip, food and water is going to be hard to come by. Besides, I can walk farther in a day than they can.”
“Well, I can't. Neither can my men. If you walk on foot and we ride on horseback, we will meet once a day. You passing us as we make camp for the evening. And we need you to guide us. Perhaps when you travel alone, or with no one but some of your fellow rangers, it is practical for you to walk on foot. But in this case, it makes more sense for you to ride with us.”
Adon eyed the horses. They would probably kick at him the moment he got close enough. Well, let them try. He had faced monsters worse than this.
Straightening his shoulders he growled. “Alright. I'll ride.”

Ligyrophobia

A reclusive and quiet character may have this fear, as may as a character who hates loud noises. For example: A guide, bard and ranger all walked into the temple of Puis. The Ranger steps on a pressure plate activating a trap which hurls arrows in front of the party. The Bard yells "Stupid elf! Mind where you put your clumsy feet!". The Ranger quietly shuffles away and is reluctant to go near the Bard for a few 4 minutes.